如何可视化您的图表¶

本指南介绍了如何可视化您创建的图表。这适用于任何图表.

设置¶

首先，让我们安装所需的包

在 [ ]

%%capture --no-stderr
%pip install -U langgraph

%%capture --no-stderr %pip install -U langgraph

设置图表¶

您可以可视化任何任意图表，包括StateGraph。让我们通过绘制分形来享受乐趣：）。

在 [1]

import random
from typing import Annotated, Literal

from typing_extensions import TypedDict

from langgraph.graph import StateGraph, START, END
from langgraph.graph.message import add_messages


class State(TypedDict):
    messages: Annotated[list, add_messages]


class MyNode:
    def __init__(self, name: str):
        self.name = name

    def __call__(self, state: State):
        return {"messages": [("assistant", f"Called node {self.name}")]}


def route(state) -> Literal["entry_node", "__end__"]:
    if len(state["messages"]) > 10:
        return "__end__"
    return "entry_node"


def add_fractal_nodes(builder, current_node, level, max_level):
    if level > max_level:
        return

    # Number of nodes to create at this level
    num_nodes = random.randint(1, 3)  # Adjust randomness as needed
    for i in range(num_nodes):
        nm = ["A", "B", "C"][i]
        node_name = f"node_{current_node}_{nm}"
        builder.add_node(node_name, MyNode(node_name))
        builder.add_edge(current_node, node_name)

        # Recursively add more nodes
        r = random.random()
        if r > 0.2 and level + 1 < max_level:
            add_fractal_nodes(builder, node_name, level + 1, max_level)
        elif r > 0.05:
            builder.add_conditional_edges(node_name, route, node_name)
        else:
            # End
            builder.add_edge(node_name, "__end__")


def build_fractal_graph(max_level: int):
    builder = StateGraph(State)
    entry_point = "entry_node"
    builder.add_node(entry_point, MyNode(entry_point))
    builder.add_edge(START, entry_point)

    add_fractal_nodes(builder, entry_point, 1, max_level)

    # Optional: set a finish point if required
    builder.add_edge(entry_point, END)  # or any specific node

    return builder.compile()


app = build_fractal_graph(3)

import random from typing import Annotated, Literal from typing_extensions import TypedDict from langgraph.graph import StateGraph, START, END from langgraph.graph.message import add_messages class State(TypedDict): messages: Annotated[list, add_messages] class MyNode: def __init__(self, name: str): self.name = name def __call__(self, state: State): return {"messages": [("assistant", f"Called node {self.name}")]} def route(state) -> Literal["entry_node", "__end__"]: if len(state["messages"]) > 10: return "__end__" return "entry_node" def add_fractal_nodes(builder, current_node, level, max_level): if level > max_level: return # Number of nodes to create at this level num_nodes = random.randint(1, 3) # Adjust randomness as needed for i in range(num_nodes): nm = ["A", "B", "C"][i] node_name = f"node_{current_node}_{nm}" builder.add_node(node_name, MyNode(node_name)) builder.add_edge(current_node, node_name) # Recursively add more nodes r = random.random() if r > 0.2 and level + 1 < max_level: add_fractal_nodes(builder, node_name, level + 1, max_level) elif r > 0.05: builder.add_conditional_edges(node_name, route, node_name) else: # End builder.add_edge(node_name, "__end__") def build_fractal_graph(max_level: int): builder = StateGraph(State) entry_point = "entry_node" builder.add_node(entry_point, MyNode(entry_point)) builder.add_edge(START, entry_point) add_fractal_nodes(builder, entry_point, 1, max_level) # Optional: set a finish point if required builder.add_edge(entry_point, END) # or any specific node return builder.compile() app = build_fractal_graph(3)

Mermaid¶

我们还可以将图表类转换为 Mermaid 语法。

在 [3]

print(app.get_graph().draw_mermaid())

print(app.get_graph().draw_mermaid())

%%{init: {'flowchart': {'curve': 'linear'}}}%%
graph TD;
	__start__([<p>__start__</p>]):::first
	entry_node(entry_node)
	node_entry_node_A(node_entry_node_A)
	node_entry_node_B(node_entry_node_B)
	node_node_entry_node_B_A(node_node_entry_node_B_A)
	node_node_entry_node_B_B(node_node_entry_node_B_B)
	node_node_entry_node_B_C(node_node_entry_node_B_C)
	__end__([<p>__end__</p>]):::last
	__start__ --> entry_node;
	entry_node --> __end__;
	entry_node --> node_entry_node_A;
	entry_node --> node_entry_node_B;
	node_entry_node_B --> node_node_entry_node_B_A;
	node_entry_node_B --> node_node_entry_node_B_B;
	node_entry_node_B --> node_node_entry_node_B_C;
	node_entry_node_A -.-> entry_node;
	node_entry_node_A -.-> __end__;
	node_node_entry_node_B_A -.-> entry_node;
	node_node_entry_node_B_A -.-> __end__;
	node_node_entry_node_B_B -.-> entry_node;
	node_node_entry_node_B_B -.-> __end__;
	node_node_entry_node_B_C -.-> entry_node;
	node_node_entry_node_B_C -.-> __end__;
	classDef default fill:#f2f0ff,line-height:1.2
	classDef first fill-opacity:0
	classDef last fill:#bfb6fc

PNG¶

如果需要，我们可以将图表渲染为 .png。这里我们可以使用三个选项

• 使用 Mermaid.ink API（不需要额外的包）
• 使用 Mermaid + Pyppeteer（需要 pip install pyppeteer）
• 使用 graphviz（需要 pip install graphviz）

使用 Mermaid.Ink¶

默认情况下，draw_mermaid_png() 使用 Mermaid.Ink 的 API 来生成图表。

在 [4]

from IPython.display import Image, display
from langchain_core.runnables.graph import CurveStyle, MermaidDrawMethod, NodeStyles

display(
    Image(
        app.get_graph().draw_mermaid_png(
            draw_method=MermaidDrawMethod.API,
        )
    )
)

from IPython.display import Image, display from langchain_core.runnables.graph import CurveStyle, MermaidDrawMethod, NodeStyles display( Image( app.get_graph().draw_mermaid_png( draw_method=MermaidDrawMethod.API, ) ) )

使用 Mermaid + Pyppeteer¶

在 [ ]

%%capture --no-stderr
%pip install --quiet pyppeteer
%pip install --quiet nest_asyncio

%%capture --no-stderr %pip install --quiet pyppeteer %pip install --quiet nest_asyncio

在 [5]

import nest_asyncio

nest_asyncio.apply()  # Required for Jupyter Notebook to run async functions

display(
    Image(
        app.get_graph().draw_mermaid_png(
            curve_style=CurveStyle.LINEAR,
            node_colors=NodeStyles(first="#ffdfba", last="#baffc9", default="#fad7de"),
            wrap_label_n_words=9,
            output_file_path=None,
            draw_method=MermaidDrawMethod.PYPPETEER,
            background_color="white",
            padding=10,
        )
    )
)

import nest_asyncio nest_asyncio.apply() # Required for Jupyter Notebook to run async functions display( Image( app.get_graph().draw_mermaid_png( curve_style=CurveStyle.LINEAR, node_colors=NodeStyles(first="#ffdfba", last="#baffc9", default="#fad7de"), wrap_label_n_words=9, output_file_path=None, draw_method=MermaidDrawMethod.PYPPETEER, background_color="white", padding=10, ) ) )

使用 Graphviz¶

在 [ ]

%%capture --no-stderr
%pip install pygraphviz

%%capture --no-stderr %pip install pygraphviz

在 [6]

try:
    display(Image(app.get_graph().draw_png()))
except ImportError:
    print(
        "You likely need to install dependencies for pygraphviz, see more here https://github.com/pygraphviz/pygraphviz/blob/main/INSTALL.txt"
    )

try: display(Image(app.get_graph().draw_png())) except ImportError: print( "You likely need to install dependencies for pygraphviz, see more here https://github.com/pygraphviz/pygraphviz/blob/main/INSTALL.txt" )